Mobile’s Rise Poses a Riddle for Banks

Popularity of Mobile Banking Means New Challenges

A waitress from Queens, N.Y., Ethel Bueno represents the promise—and the pitfalls—of a recent surge in the popularity of mobile banking.

The 23-year-old keeps her phone close at all times, and frequently logs on to her Capital One bank account to check her balance and make sure charges go through correctly. “It’s made my life easier,” she says.